Honey crusted impetigo???

[jngo2]

Kaplan says that honey crusted impetigo is caused by Strept pyogenes. But most of the resources I've seen online have said that most impetigo is caused by Staph which can present with a crusty lesion...so which is it?

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[lord_jeebus]

I would doubt that Step I would expect you to identify which organism is causing the impetigo from clinical presentation alone.

In the very unlikely event that it did, I'd go with S. aureus.

 

[crys20]

It can be caused by either S. aureus or Strep pyogenes, but S. aureus is the more common cause.

 

[werd]

whatever the cause is, "honey crusted impetigo" sounds delicious.

 

[jhrugger]

we learned it this way... honey crusted is more indicative of strep pyogenes, but staph a is also a possible cause. so basically both can cause it but it is more associated with strep pyogenes.

hope that helps 🙂

 

[UCLAstudent]

Per BRS Pediatrics, Staph aureus is the most common cause of impetigo, while Strep is the most common cause of erysipelas.

The chief of dermatology at my school taught us that the honey crusts are actually because colonies of S. aureus are gold-colored in culture (aureus = gold). But Strep can also cause honey-crusted impetigo, so there goes that theory. 😉

 

[RobertBusch]

I have been struggling with this same question myself for the last 1/2 hr.

Here are some useful facts.
Staph Aureus: Is Gold on Sheeps Blood Agar (not on skin infections). When it infects the skin it is more bullous then crusts over.

Strep: Causes the honey crusted lesions. Remember this mortality is 50% so very important to know.

Yes the Step 1 could ask this. I have had this question in Kaplan and in USMLEWorld Qbanks.

 

[wAyRadikull]

I'm not sure where I came across this question, I think it was UW but I could be wrong, but in the vignette they talked about a "skin infection" which was basically describing impetigo. The kid in the vignette later on went to get PSGN therefore indicating that S.Pyogenes was the culprit. So I guess the differentiating factors lie in the sequelae (sp?) of the lesion.

RR Path: 545
S.aureus: MCC
S.pyogenes: 2nd MCC

 

[NREMTP]

I always thought it was more likely S. Pyogenes in kids and S. Aureus in adults. Not sure where I read that.

 

[turkeyjerky]

Per BRS Pediatrics, Staph aureus is the most common cause of impetigo, while Strep is the most common cause of erysipelas.

The chief of dermatology at my school taught us that the honey crusts are actually because colonies of S. aureus are gold-colored in culture (aureus = gold). But Strep can also cause honey-crusted impetigo, so there goes that theory. 😉

Haha, i like the logic.

Strep: Causes the honey crusted lesions. Remember this mortality is 50% so very important to know.

wtf?

I'm not sure where I came across this question, I think it was UW but I could be wrong, but in the vignette they talked about a "skin infection" which was basically describing impetigo. The kid in the vignette later on went to get PSGN therefore indicating that S.Pyogenes was the culprit. So I guess the differentiating factors lie in the sequelae (sp?) of the lesion.

Yeah, the ****ty part of it is that staph infections, rarely, can also lead to post-infectious glomerulonephritis. (not sure if staph impetigo can though)


Here's what we learned in derm pathophys. There are both bullous and non-bullous forms of impetigo. The bullous form is pure staph, whereas the non-bullous form starts as a strep infection and is later contaminated by staph. This is the one classically associated with honey colored crusts and a possibility of psgn.

 

[Captopril]

Honey crusted impetigo = Always SA. I don't care if the stem says that the bacteria got a megaphone and said "I am S. Pyogenes". It's still SA.

 

[deleted103644]

Here's a link to some images. Impetigo can be caused by both S. Aureus and S. pyogenes, with aureus causing most of the bullous impetigo and strep causing most of the non-bullous (aka crusted) impetigo.

http://emedicine.medscape.com/article/1052709-media


Nonbullous (crusted) impetigo (strep)

Bullous impetigo (staph)